1. Introduction to and History of Fluoroscopy Radiation Protection
Based on:
Syllabus on Fluoroscopy Radiation Protection, 6th Revision
California Department of Health Services
Created by: Jed Miles, BSRS, RT(R), CRT-CA

2. Syllabus
Current version is 6th revision of “Syllabus on Fluoroscopy Radiation Protection” written in 1975
Fluoroscopic systems have vastly improved during the next 3+ decades
Most new fluoroscopic system installations utilize digital technology
California State “Technologist Fluoroscopic Permit” examination questions are based on this revision
New syllabus is being written and is in final stages of acceptance and adoption by the Radiology Health Branch of California

3. Historical Development of Fluoroscopy
William Roentgen
November 8, 1895: noticed a barium platinocyanide screen fluorescing as a result of being exposed to what he would later call x-rays
Thomas Edison
A few months later (1896), discovered that calcium tungstate screens produced brighter images.
Credited with designing and producing the first commercially available fluoroscope

4. Early Fluoroscopic Imaging
Early fluoroscopic imaging consisted of an x-ray tube coupled with a specialized image receptor
Called a conventional fluoroscopy screen
Live or dynamic images could be viewed on this screen during continuous x-ray exposure

5. Early Radiation Exposure
While performing a fluoroscopic study, radiologists received full dose of transmitted primary beam to upper torso and face
Many radiologists developed leukemia and died, thus becoming martyrs for radiologic science
Once the biological hazards became apparent, the design of the fluoroscope was changed to permit viewing through an arrangement of mirrors.
Later fluoro screens were attached to table

6. Mirrored Fluoroscopy
Arrangement of mirrors shielded the primary beam because:
X-ray tube mounted under (inside) the table
Conventional fluoroscopic screen mounted over table and contained within lead-lined canister
Series of mirrors permit viewing image without direct radiation exposure to face and upper body
Primary beam contained within a lead-lined enclosure

7. Human Eye – Rods and Cones
Visual acuity is the ability to perceive small objects
Rods and cones are structures in the eye responsible for the sensation of vision
Rods:
Scotopic (night) vision
Sensitive to low level light
Essentially colorblind
Cones:
See fine details in objects and perceive contrast
Photopic (day) vision
Sensitive to high or intense light level situations
Used for color vision

8. Human Eye and Fluoroscopy
Photopic visual acuity is 10x’s greater than scotopic
Requires brightness 1,000 times greater than that of a conventional fluoroscopic screen
Early conventional fluoro screens produced a very dim image
Dark adaptation time of minutes was required to activate the rods
Exclusive use of retinal rods to view the image constituted a threat to diagnostic accuracy

9. Image Intensification Tubes
1948: Major breakthrough in technology
Evacuated glass image intensification tube developed as image receptor
Achieved same brightness of image while using a lower dose rate
Enabled video cameras and TV viewing monitors to replace mirror viewing systems
Technology was crude and resulted in a loss of detail compared to mirrored viewing system
Paved the way for the methods of fluoroscopic viewing in use today.

10. Modern Image Intensifiers
Modern image intensifiers are designed to electronically amplify the brightness of an image in a range of 500 – 8,000 times

11. What’s Next?
Please close this PowerPoint presentation, and then click Discussion 1 to continue.